Kokoro Research Center, Kyoto University, Japan.
Isehara Technical Center, Tanaka Kikinzoku Kogyo K.K., Japan.
Magn Reson Imaging. 2022 Jan;85:19-27. doi: 10.1016/j.mri.2021.10.002. Epub 2021 Oct 13.
Magnetic resonance imaging (MRI) devices are frequently used in image-based diagnosis. In the case of large artifacts, which are generated in magnetic resonance (MR) images when magnetic materials, such as metals, are present in the body, these devices are less useful. This study aimed to develop a dual-phase Au-Pt alloy that does not generate artifacts in MR images and has high workability to prepare medical devices.
A processing method to produce a dual-phase Au-Pt alloy was established, and the magnetic susceptibility and artifacts of different alloy compositions were determined using a SQUID (superconducting quantum interference device) flux meter and a 1.5 T-MRI system. The crystallographic phases of the prepared alloy samples were identified using X-ray diffraction. Sample cross-sections were observed using a metallurgical microscope. Furthermore, a thinning test was conducted to examine alloy workability.
Dual-phase Au-Pt alloys Au70Pt30 and Au67Pt33-the former heat-treated at 800 and 850 °C and the latter heat-treated at 900 °C-generated minimal artifacts when imaged in a 1.5 T-MRI system. Their volume magnetic susceptibility increased as the heat-treatment temperature decreased. The alloy surfaces were observed to be uniform. Moreover, the workability of the dual-phase alloy was considerably better than that of the single-phase alloy.
Volume magnetic susceptibility could be controlled by changing the composition and processing temperature of the Au-Pt alloys. Dual-phase Au-Pt alloys those do not generate magnetic susceptibility artifacts in MRI images and have good workability could be prepared. The alloys are expected to be used in the preparation of various implantable medical devices.
磁共振成像（MRI）设备常用于基于图像的诊断。然而，当人体存在磁性材料（如金属）时，会在磁共振（MR）图像中产生较大的伪影，从而降低这些设备的使用效果。本研究旨在开发一种不会在 MR 图像中产生伪影且具有良好加工性能的双相 Au-Pt 合金，以用于制备医疗器械。
建立了一种生产双相 Au-Pt 合金的加工方法，并使用超导量子干涉装置（SQUID）磁通计和 1.5T-MRI 系统确定了不同合金成分的磁化率和伪影。采用 X 射线衍射对制备的合金样品的晶体相进行了鉴定。利用金相显微镜观察了样品的横截面。此外，还进行了减薄试验以检验合金的加工性能。
在 1.5T-MRI 系统中成像时，双相 Au-Pt 合金 Au70Pt30（经 800°C 和 850°C 热处理）和 Au67Pt33（经 900°C 热处理）产生的伪影最小。随着热处理温度的降低，它们的体积磁化率增加。合金表面观察到均匀。此外，双相合金的加工性能明显优于单相合金。
通过改变 Au-Pt 合金的成分和加工温度，可以控制其体积磁化率。可以制备出不会在 MRI 图像中产生磁化率伪影且具有良好加工性能的双相 Au-Pt 合金。这些合金有望用于制备各种植入式医疗器械。
